Rotational casting apparatus



Dec. 31, 1963 E. SODERQUIST 3,115,680

ROTATIONAL CASTING APPARATUS Filed Aug. 25, 1962 6 Sheets-Sheet l S TRIPP! NG LOA DING INVENTOR F, G I LESLIE E. SODEROUIST ATTORNEYS Dec. 31, 1963 E. SODERQUIST ROTATIONAL CASTING APPARATUS Filed Aug. 25, 1962 6 Sheets-Sheet 2 FIG.2

INVENTOR. LESLIE E. SODEROUIST A BY M, 17 r/C ATTORNEYS;

Dec. 31, 1963 E. SODERQUIST 3,11

ROTATIONAL CASTING APPARATUS Filed Aug. 23, 1962 6 Sheets-Sheet 3 K A I38 \I32 \I2I 45 (STRIPPING a A 30 LOADING) A l I: I 40 J G 4' L3 F I 3 INVENTOR.

LESLIE E. SODEROUIST BY Maw ATTORNEYS Dec. 31, 1963 L. E. SODERQUIST ROTATIONAL CASTING APPARATUS 6 Sheets-Sheet 6 Filed Aug. 23, 1962 FIG.6

I INVENTOR. LESLIE E. SODEROUIST z ATTORNEYS United States Patent 3,115,684) ROTATEQNAL CASTING APPARATUS Lesiie E. oderquist, Silver Lake, Ohio, assignor to The lvlicNeii Machine 8?: Engineering Company, Akron,

(E hic, a corporation of Ghio Filed Aug. 23, 1962, Ser. No. 219,039 12 tClaims. (Cl. 1826) The present invention relates to improved forms of rotational casting apparatus.

A process of rotational casting is practiced in the making of hollow articles from vinyl plastisols. As described and claimed in US. Patent No. 2,629,134, the process may be briefly described as follows: A hollow sectional mold is charged with a measured amount of fluid plastisol mixed with vinyl resin and then closed. The mold is rotated in a compound manner about two axes and at the same time is heated. The mixture is distributed over or forced against the interior surface of the mold and as the temperature of the material rises the mixture gels and a film is uniformly distributed on the interior surface of the mold. Ieating is continued until the mixture reaches the fusion temperature, usually around 350 F. At this temperature the liquid plasticizer is fused with the divided particles of the vinyl resin. The mold is then cooled and the cooling process gives the mixture tensile strength. The mold is opened and the finished article is removed.

An improvement in the rotational casting process of the aforesaid Patent No. 2,629,134 is described and claimed in US. Patent 3,044,124. This is a process for the rotational casting of intricate articles and may be briefly described as follows: The closed mold is subjected to centrifugal forces during rotation on a single axis While raising the temperature of the mold to the gelling temperature of the plastisol charge. Then, and before the plastisol has gelled beyond a thin outer layer, the mold is subjected to simultaneously applied weaker rotative forces on divergent axes while the temperature of the mold is raised to the fusion temperature of the plastisol. During cooling of the mold following fusion of the plastisol, the mold may be further subjected to weaker centrifugal forces on the single axis.

it is the general object of the present invention to provide novel apparatus for rotating molds, and the mold carriers or mounting means, for practice of the process of rotational casting.

Further, it is an object to provide apparatus suitable for practice of the rotational casting process of aforesaid Patent No. 2,629,134.

Still further, it is an object to provide apparatus specifically and particularly well suited for practice of the rotational casting process of aforesaid Patent No. 3,044,124.

These and other objects of the invention, as well as advantages thereof, will be apparent in view of the following detailed description and of the attached drawings.

in the drawings:

PEG. 1 is a plan view showing orientation of the apparatus at stations for stripping and loading, for curing, and for cooling;

FIG. 2 is an enlarged fragmentary plan view showing details of the apparatus drive and indexing mechanisms;

FIG. 3 is a sectional elevation, at the stripping and loading station, taken substantially as indicated on line 33 of FIG. 2;

FIG. 4 is another sectional elevation, at the curing station, taken substantially as indicated on line 44 of FIG. 2;

FIG. 5 is still another sectional elevation, at the cooling station, taken substantially as indicated on line 5-5 of FIG. 2;

Patented Dec. 31, T5363 FIG. 6 is a detail section, showing the indexing mechanism, taken substantially as indicated on line 66 of FIG. 2; and

FIG. 7 is a detail section, showing the drive elements at the cooling station, taken substantially as indicated on line 7-7 of FIG. 2 and P16. 5.

Throughout the drawings, a preferred form of casting apparatus according to the invention is indicated by generally the numeral lil. The mold carriers are indicated generally by the numeral 12. The curing oven, for heating the molds, is indicated generally by the numeral i i. The cooling hood is indicated generally by the numeral 16. The stripping and loading station is designated A, the ouring or oven station is designated B, and the cooling station is designated C.

In general, a rotational casting apparatus 10 according to the invention has a base, a turret rotatably mounted above the base, and a plurality of arms extending radially of the turret for mounting of mold carriers 12. Each mold carrying arm includes an outer tubular shaft coaxially rotatable around an inner shaft. On each of the inner and outer shafts are individual axially aligned rotatable drum means. Beneath the turret, a plurality of resilient drive wheels for the mold carrying arms are mounted radially of the base. The drive wheels are located to frictionally engage the undersurface portions of the drum means for rotation of the mold carriers 12 by rotation of the carrying arm shafts. Also, at least one of the drive wheels is located to engage the undersurface of the turret for rotation of the mold carrying arms from station-tostation. Power means are provided to selectively rotate the drive wheels. Mechanical elements are provided to selectively maintain either all of the rotating drive wheels in frictional engagement with the drum means, or at least one of the rotating drive wheels in engagement with the turret undersurface.

Base and Drive As best shown in FIG. 4, the casting machine it} includes a base plate 26 having a pedestal 21 supporting a vertically aligned bearing 22 and bearing retainer ring 23. The bearing 22 rotatably carries the lower end of .a vertically aligned axial post shaft 25. The shaft 25 rotatably mounts the casting machine turret for station-to-station movement of the mold carrying arms, as described in detail below.

Extending upwardly from the base plate 20 are three vertical plates 27, 2t and 29, (see FIG. 2) which define the side walls of a generally triangularly shaped stationary base housing, designated generally by the numeral 3%. The base housing 36 encloses the lower portion of shaft 25 and provides mounting for elements of the drive mechanisms for the mold carrying arms and for electrical control elements, all as described in detail below. A web plate 31 interconnects the upper ends of the vertical plates 27, 28 and 29 and carries an axial flange 32- with a sleeve bushing 33 journaling the medial portion of shaft 25.

The casting apparatus 10 is particularly characterized by having individual and separately controlled drive means for each station of the casting operation. The drive at the stripping and loading station A is designated by the numeral 35. The drive 35 provides the power for selectively positioning the molds on carriers 12 in positions suitable for opening and removal of cured articles and for charging with materials to be cast. Also, if required by the particular process being practiced, the closed molds can be subjected to rotative forces prior to application of curing heat.

The drive at the curing or oven station B is designated by the numeral 36. The drive 36 provides power for selectively rotating the molds on a single axis or on divergent axes, at varied speeds and degrees of relative rotation.

The drive at the cooling station C is desi nated by the numeral 3'7. The drive 37 provides power for rotating the molds while cooling after emergence from the oven. By a unique use of rotational forces, the drive 37 also provides the power for station-to-station movement of the casting apparatus turret, as described in detail below.

The stripping and loading station drive 35 is preferably located radially of the axial shaft 25 and the intersection of vertical plates 27 and 23 of the base housing Referring specifically to FIG. 3, the drive at station A includes an AC. motor 49 mounted on the base plate 24} and connected to a speed reduction unit 4-1 having an output shaft 42. Fitted on the output shaft 42 is a small diameter, single sprocket 23. A chain 44- is trained under the sprocket 43 and up and around a larger diameter sprocket 45.

The upper sprocket 45 is secured on the medial portion of an elongated hub sleeve d6 having axial bore for rotatable mounting on a fixed horizontally extending shaft 47. The inner end of the shaft 47 is secured within the base housing by a block d3 mounted on the underside of the web plate 51. outwardly of the sprocket 45, the projecting end of the sleeve 46 carries a single drive wheel assembly, designated by the numeral 5th The drive wheel assembly St) includes a rim 51 mounting a pneumatic tire 52. The the 52, which is of conventional construction and inflated to a pressure of for example 30-80 p.s.i., provides a resilient clutch and force transmission means selectively engaging the drum means on the inner shaft of each mold carrying arm for major axis rotation of the mold carriers 12. As shown, the rim 51 is of two-piece construction having mating radially inner flanges 53 secured by bolts 54 to a shoulder 55 on the hub sleeve 46.

The curing or oven station drive as is preferably located radially of the axial shaft and the intersection of vertical plates 28 and 29 of the base housing 3d. Referring specifically to FIG. 4, the drive at station B includes two DC. motors separately mounted on the base plate. The radially outer motor till, for driving the outer shaft of each mold carrying arm for so-called minor axis rotation of the mold carriers 12, as explained in detail below, is connected to a speed reduction unit 61 having an output shaft 62. Fitted on the output shaft 62 is a small diameter single sprocket 6 3. A chain 64 is trained under the sprocket 63 and up and around a larger diameter sprocket 65.

The upper sprocket 65 is secured on the projecting outer end of an elongated hub sleeve 65 having an axial bore for rotatable mounting on a fixed horizontally extending shaft 67. The inner end of the shaft 6'7 is received in the bore of a block 6 8 secured to the base housing 30. When inserted in the block 68, the shaft 67 is secured to the base housing by a bolted face plate as.

The second or radially inner motor 76 of the curing station drive 36, for driving the inner shaft of the mold carrying arm for major axis rotation of the mold carriers 12, is connected to a speed reduction unit 71 having an output shaft 72. Fitted on the output shaft 72 is a small diameter single sprocket 73. A chain 74 is trained under the sprocket 73 and up and around a larger diameter sprocket 75. The upper sprocket 75 is secured on the radially outer end of an elongated hub sleeve 76, similar to sleeve 66 and also having an axial bore for rotatable mounting on the shaft 67 radially inward of the sleeve 66.

The curing station drive 36 has a double wheel assembly, designated by the numeral Sit. An outer rim 81 monuting a pneumatic tire 82, similar to rim S1 and tire 52, described above, is secured by bolted flanges 83 to a shoulder 84 on the minor axis hub sleeve 66. A similar inner rim 85 and pneumatic tire 86 is secured by 4 bolted flanges 87 to a shoulder $8 on the major axis hub sleeve 76.

The cooling station drive 37 is preferably located radially of the shaft and the intersection of vertical plates 27 and 29 of the base housing 35!. Referring specifically to FIG. 5, the drive at station C includes an A.C. motor 91; mounted on the base plate Ztl and connected to a speed reduction unit 91 having an output shaft 92. Fitted on the output shaft 92 is a small diameter double sprocket 93. A chain 9'4 is trained under the radially outer sprocket portion (93a) and up and around a larger diameter sprocket 95.

The upper sprocket 95 is secured on the radially inner end of an elongated hub sleeve )6 having an axial bore for rotatable mounting on a fixed horizontally extending shaft 97. The inner end of shaft 97 is secured within the base housing 36 by a block 98, similar to block 48 described above, mounted on the underside of the web plate 31.

To provide that the degree of major and minor axis rotation of the mold carriers during rotation at station C is substantially the same, it is preferred that the radially inner sprocket (9327) on the output shaft 92 of the speed reduction unit be connected by a chain $9 to an idler sprocket 1%. As shown in FIGS. 2 and 7, the double idler sprocket 1% is secured on a horizontal shaft 101 rotatably journaled in a bracket 1% mounted on the base plate 211. The large diameter radially outer sprocket (183a) is connected by the chain 99 to the sprocket 93b. A chain 104 is trained under the radially inner sprocket (1110b) and up and around a larger diameter sprocket 11115. The upper sprocket 1&5 is secured on the radially outer end of an elongated sleeve 1%, also having an axial bore for rotatable mounting on the shaft 97 radially inward of the sleeve 96.

The double wheel assembly of the cooling station drive 37 is designated by the numeral 110. The outer rim 111 mounting a pneumatic tire 112, similar to rim 51 and tire 52 described above, is secured by bolted flanges to a shoulder 114 on the minor axis hub sleeve 96. A similar inner rim 115 and pneumatic tire 116 is secured by bolted flanges 117 to a shoulder 11% on the major axis and turret rotation hub sleeve 136.

It will be noted from the above description and by a comparison of FIGS. 3 and 5 with FIG. 4, that the mounting of the horizontal shafts 47 (of drive 35) and 97 (of drive 37) on the base housing is different from the mounting of the horizontal shaft 67 of drive 36'. Because the casting machine 143* is operated when locatedv in close proximity to the curing oven 14 (see FIG. 1),. the provision of a housing block 68 and the bolted face plate 69 which will facilitate removal or replacement of the wheel assembly 80 for maintenance purposes, is to. be preferred.

Turret and Mold Carrying Arms The arms for carrying the molds and carriers 12 are indicated generally by the numeral 120 In the form of the invention shown, there are three identical mold carrying arms 12d equally spaced (128 apart) extending radially of and horizontally from within a casting machine turret assembly.

As best shown in FIG. 4, the turret assembly includes a bottom plate 121 which is substantially circular, a series of vertical reinforcing ribs 122 extending radially from an axial hub 123 mounting the turret plate 121 on the post shaft 2 5, and a smaller diameter substantially circular top plate 124. To raise or lower the turret assembly small distances in relation to the drive tires of the wheel assemblies 51), fill and 11% it is preferred that the top plate 124 have an axial member 125 with an adjustable bolt 126 engaging the upper end of the post 25.

Each mold carrying arm 120 includes a long solid inner shaft 128 rotatably journaled in a bearing block 129 located between the top and bottom plates of the turret assembly, preferably on one or more of the reinforcing ribs 122. The shaft 128 is driven by a power drum 130 to rotate the mold carriers 12 on their major axis. Each power drum 130 has a hub portion 131 secured to the shaft 123 and a surface portion 132 for frictional engagement with the crest portion of a tire (52, 86 or 116) of the drive wheel assemblies 56, 8d and 11%.

Axially outward of the hub portion 131 of a power drum 131? a bearing 134 is fitted on shaft 128. The bearing 13d rotatably mounts an outer power drum 135 which drives the outer tubular shaft 136, coaxially enclosing the outer portion of a shaft 123, to rotate the mold carriers 12 on their minor axis. Each power drum 135 has a hub adapter 137 secured to the inner end of shaft 136 and a surface portion 138 for frictional engagement with the crest portion of a tire (82 or 112) of the stations B and C and drive wheel assemblies 8% and 110.

The outer end of each shaft 128 carries a transmission block 149 which is substantially T-shaped in cross-sec tion. A short cross-shaft 141 is rotatably journaled Within the block 140 transversely of the shaft 128. At one end, the cross-shaft 141 has an extension 141a to which a mitre gear 142 is affixed. The outer end of shaft 136 carries a mitre gear 143, journaled on a bearing 144, which meshes with the gear 142. Thus, rotation of the inner shaft 128 causes the block 14th to rotate on the same or the major axis. Rotation of the outer shaft 136, through gears 143 and 142, causes the cross-shaft 141 to rotate on a transverse or minor axis.

The mold carriers 12, which are of a suitable and conventional construction (see, for example, US. Patent No. 3,000,056), are preferably used in pairs for the purpose of weight balance. One mold carrier could be attached to the cross-shaft 141 as by a stud block 146 and the opposite mold carrier could be attached to the outer face of the mitre gear 142.

Station-to-Szation Rotation and Indexing Referring to the detailed plan view FIG. 2, it will be noted that the periphery of the turret bottom plate 121 is provided with the two sets of notches. There are three equally spaced (120 apart) wide notches 1% each having downwardly tapered side walls 151. The radial center line of each notch 151 is directly below the axial center line of a mold carrying arm 12% The width of each notch 159 is established by the diameter of the inner power drum 13d of the arms 120. As shown in the detailed sectional views, particularly FIG. 4-, the surface portion 132 of each power drum 13d lies closely adjacent the tapered notch side walls 151 and substantially flush with the undersurface 121a of the turret bottom plate.

The second set of notches 152 are also equally spaced, but are narrower than the notches The notches 152 cooperate with a turret index and lock mechanism, described in detail below. As shown, there are six notches 152. Three notches 152 (spaced 120 apart) are used to lock and maintain the turret and arms 12%) in the operating positions at stations A, B and C. The other three notches (also spaced 120 apart) are used to provide an intermediate position during station-to-station movements, for purposes such as opening and closing the doors of the curing oven 14.

As stated above, the motor 90 of tne cooling station drive 37 is utilized to rotate the casting machine turret and the mold carrying arms (120) from station-to-station. Referring specifically to FIG. 5, it will be noted that the inner tire 116 of the drive wheel assembly 11% is located adjacent the base housing 30 and beneath the turret plate 121. When a turret plate notch th is aligned exactly above the tire 116, the inner drum 13d of an arm 12%) will be frictionally engaging or riding upon the crest of the tire 116. When the motor 90 is energized, both the inner drum 130 and the outer drum 135 of an arm 120 will be rotated.

So long as the turret assembly carrying the arms 1% is positively maintained or locked in position, the driving force of the tire 116 will only rotate the power drum 130. However, if the turret assembly is unlocked and free to rotate around the axial post shaft 25, the driving force of the tire 116 will impart an initial momentum to the power drum 13d, and the turret assembly, so that the rotating tire 116 then engages the undersurface (121a) of the turret bottom plate for rotational advance of the turret assembly.

Referring to FIGS. 2 and 6, the rotation of the turret assembly and of the arms 12% from station-to-station is controlled by an index and lock mechanism indicated generally by the numeral 160. As shown, the assembly 16% is carried by a bracket 161 mounted on a lateral extension on the base housing web plate 31, radially outwardly of plate 28 and between stations A and B. The assembly 1-64) preferably utilizes two pneumatic cylinder means to perform the turret index and lock functions. A first cylinder 1&2 is attached to a mounting block and extension 163 pivotally mounted on a shaft 164 extending horizontally from the vertical face of bracket 161. The vertically extendible shaft 165 of cylinder 162 carries a block 166 rotatably mounting a control roller 167, having a diameter permitting entry and withdrawal from within the narrow turret plate notches 152.

The second cylinder 163 is carried by a base fitting 169 movably mounted on a substantially horizontally extendible shaft 17). The cylinder shaft 171 extends laterally toward the first cylinder shaft 165 and carries an adjustable clevis 172 with ear flanges 1'73 engaging the block 166 mounting the control roller 167.

During the casting operations at stations A, B and C, the first cylinder shaft 165 is normally extended so that the roller 167 is engaged, or is tending to engage, within the confines of a plate notch 152. When the casting machine turret is to be rotated from station-to-station, using conventional control means such as electrical solenoids, the cylinder 162 is deenergized to retract shaft 165 and, preferably simultaneously, cylinder 168 is energized to extend shaft 171. Thus, the control roller 16'? is simultaneously lowered and directed toward the chain-line position of FIG. 6, presenting the minimum of interference with rotative driving force applied by the wheel 116 of assembly 11% to the undersurface 121a of the turret bottom plate. After turret rotation is begun, cylinder 162 may be energized and cylinder 168 deenergized so that the roller 1&7 will bear against the turret undersurface 121a until free to move upward and within a notch 152, stopping the turret rotation in either an operating or an intermediate position as desired or necessary.

cording the invention may be controlled by suitable electrical components for practice of various rotational castprocesses. For example, the individual motors of the station drives 3-5, 36 and 37 would require starters, actuatin-g switch means, and speed controllers. For automatic operation, a master controller, including timer and relay and interlock circuitry, could be employed. It would be preferred to also provide an optional manual control for special operations or for use when starting the apparatus on a work period. Further control could be provided to vary the rotational speeds and degree, particularly for the arm within the curing oven. These and other electrical components are not considered a part of present invention, it being understood that control elements could be selected and circuitry designed by a qualified electrical engineer having the benefit of the above disclosure and the drawings, and with knowledge of the casting processes to be performed.

It is also apparent that various changes and modifications could be made to the preferred form of apparatus 16 which has been described. Thus, the drive 35 at station A could rotate the minor axis p wer drum 126, or,

the drive 37 at station C could rotate only the mailer axis power drum 13% and the turret. Rather than chains and sprockets as shown, the drives 35, 3d and 37 could empoly pulleys and V-belts. Referring to the several tires (eg. 52) of the drive wheel assemblies 5t and ill the pneumatic type tire shown is readily available at an economical price. However, a solid or semi-solid type tire could be employed so long as the properties of resilient drive were maintained. In view of these and other factors, the true spirit and scope of the invention should be determined not by details but by a fair interpretation of the appended claims.

What is claimed is:

l. In rotational casting apparatus having a base, a turret rotatabiy mounted above said base and a plurality of mold carrying arms extending radially of said turret, each said arm including an outer tubular shaft coaxially rotatable around an inner shaft, axially aligned rotatable drum means on each of said shafts, a plurality of resilient drive wheels mounted radially of said base, one of said drive wheels being located to frictionally engage one of said drum means and said turret, power means to selectively rotate said drive wheels, and means to selectively maintain said drive wheels when rotating in frictional engagement with said drum means and with said turret.

2. Rotational casting apparatus comprising a plurality of mold carrying arms extending radially of a center, each of said arms having an outer shaft coaxially rotatable around an inner shaft, mold carriers on the end of each arm, first drum means driving said outer shafts so that said mold carriers are rotated on their minor axis, second drum means driving said inner shafts so that said mold carriers are rotated on their major axis, resilient force ransmission means located to frictionally engage the undersurface portions of said drum means, and means to rotate said mold carrying arms around said center for selective engagement of said drum means by said resilient transmission means.

3. Rotational casting apparatus comprising a base plate carrying a vertically aligned axial post shaft, a series of vertical plates extending upwardly from said plate and defining a generally triangularly shaped base housing enclosing the lower portion of said shaft, a plurality of drive mechanisms located radially of said post shaft and the intersections of said vertical plates, each of said drive mechanisms having at least one resilient drive wheel mounted on a horizontal shaft extending radially of said housing, a turret rotatably mounted above said housing on said post shaft, a plurality of mold carrying arms extending radially of said turret, each said arm including an outer shaft coaxially rotatable around an inner shaft, and axially aligned rotatable drum means on each of said shafts having undersurface portions located to frictionally engage said resilient drive wheels.

4. Rotational casting apparatus according to claim 3 in which one of said drive mechanisms (35) has a resilient drive wheel which is frictionally engaged only by the drum means on the inner shafts of said mold carrying arms.

5. Rotational casting apparatus according to claim 3 in which two of said drive mechanisms (36, 37) each have two axially aligned resilient drive wheels, one of said drive wheels being frictionally engaged by the drum means on the outer shaft of said mold carrying arms and the other of said drive wheels being frictionally engaged by the drum means on the inner shaft of said mold carrying arms.

6. Rotational casting apparatus according to claim 5 in which said drive mechanism as includes two variable speed motors, each motor being individually connected to one of said resilient drive wheels.

7- otational a g app ratus according to claim 5 in whicl said drive mechanism (37) includes a motor and interconnecting linkage whereby said motor is simultaneously connected to both of said drive wheels.

8. Rotational casting apparatus comprising, a base having vertical plates defining the side walls of a base housing, a vertically alig ed post shaft extending axially of said base housing, a turret rotatably mounted on said post shaft above said base, said turret having a substantially circular bottom plate, a plurality of mold carrying arms extending radially of said turret, each said arm including a tubular outer shaft coaxially rotatable around an inner shaft, a radially outer power drum on said outer shaft and a radially inner power drum on said inner shaft, a plurality of drive mechanisms on said base located radially of said post shaft and the intersections of said vertical plates, each said drive mechanism including a drive wheel assembly mounted on a horizontal shaft extending radially of said housing, each said assembly having at least one resilient drive Wheel located on a horizontal shaft to frictional engage the undersurface portion of a mold carrying arm power drum.

9. Rotational casting apparatus according to claim 8 in which one of said drive wheel assemblies (119) has a resilient drive wheel (lid) located on a horizontal shaft (97) so as to friction-ally engage either the radially inner surface portions of the power drums (13%)) on the inner shafts (128) of each mold carrying arm (120) or the undersurface (121a) of said turret bottom plate.

10. Rotational casting apparatus according to claim 9 in which said turret bottom plate (121) has a series of equally spaced wide peripheral notches (15%), the radial center line of each notch being directly below the axial center line of a mold carrying arm, the width of each notch being established by the diameter of the power drums (A36?) on the inner shafts of each mold carrying arm, whereby the surface portion (132) of each power drum lies substantially flush with the undersurface of said turret bottom plate.

11. Rotational casting apparatus according to claim 9 in which said turret bottom plate (121) has a series of equally spaced narrow peripheral notches (7.52), selectively engaged by an index and lock mechanism (16%) mounted on said base housing (3%).

12. In rotational casting apparatus having a base, a turret rotatably mounted above said base, said turret having a substantially circular bottom plate, said bottom plate having a series of equally spaced narrow peripheral notches (152,), a plurality of mold carrying arms extending radially of said turret, and a drive providing power for rotation of said turret; mechanism for controlling said turret rotation comprising, a first cylinder (162) mounted on said base beneath said turret, said first cylind-er having a vertically cxtendible shaft (165) mounting a control element (167) having a diameter permitting entry and withdrawal from said plate notches, and a second cylinder (hi3) mounted on said base beneath said turret, said second cylinder having a laterally extendible shaft (1'79) connected to said control element, and control means for retracting said first cylinder shaft and extending said second cylinder shaft, withdrawing said control element from Within one of said notches, when said drive is rotating said turret, and extending said first cylinder shaft and retracting said second cylinder shaft, and entering said control element within one or" said notches when said turret rotation is to be stopped.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ll5 68O December 31 1968 Leslie Ea Soderquist It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 8 and 9 for "by generally" read generally by column 3, line 72 for "monuting" read mounting column 4 line 4 after "shaft" insert 25 column 7 lines 3 and 4 for "empoly" read employ column 8 line 20 for "frictional" read frictionally Signed and sealed this 30th day of June 1964,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. IN ROTATIONAL CASTING APPARATUS HAVING A BASE, A TURRET ROTATABLY MOUNTED ABOVE SAID BASE AND A PLURALITY OF MOLD CARRYING ARMS EXTENDING RADIALLY OF SAID TURRET, EACH SAID ARM INCLUDING AN OUTER TUBULAR SHAFT COAXIALLY ROTATABLE AROUND AN INNER SHAFT, AXIALLY ALIGNED ROTATABLE DRUM MEANS ON EACH OF SAID SHAFTS, A PLURALITY OF RESILIENT DRIVE WHEELS MOUNTED RADIALLY OF SAID BASE, ONE OF SAID DRIVE WHEELS BEING LOCATED TO FRICTIONALLY ENGAGE ONE OF SAID DRUM MEANS AND SAID TURRET, POWER MEANS TO SELECTIVELY ROTATE SAID DRIVE WHEELS, AND MEANS TO SELECTIVELY MAINTAIN SAID DRIVE WHEELS WHEN ROTATING IN FRICTIONAL ENGAGEMENT WITH SAID DRUM MEANS AND WITH SAID TURRET. 